Indulges in violent behaviour (8)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
rampages
(Other definitions for rampages that I've seen before include "Violent disorders" , "Rushes around wildly" , "Violent and destructive behaviours" , "Runs riot" , "Moves through a place in a violent and uncontrollable way" .)